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INTERGROWTH-21st course

Module 2Assessing Maternal Anthropometry and Weight Gain During Pregnancy

INTERGROWTH-21st

Module 2

Maternal weight gain

and anthropometry

On successful completion of this module you should be able to:

• List the instruments used for maternal anthropometry.

• Accurately measure maternal weight, height and body mass index (BMI).

• Use the INTERGROWTH-21st Gestational Weight Gain Standard for normal-weight women

INTERGROWTH-21st

Module 2


and anthropometry

• The lack of growth standards for pregnancy dating, fetal growth, maternal weight gain,

newborn size and preterm postnatal growth greatly limits our understanding of early

growth and development during pregnancy and comparisons across international

populations (Bhutta, 2013; Villar et al., 2015).

• The aetiology and epidemiology of fetal growth restriction and preterm birth syndromes

are also significantly impaired by the absence of an international standard for

intrauterine growth with which to compare deviations and identify phenotypes (Bhutta,

2013; Villar et al., 2015).

• Since optimal fetal and neonatal growth and their implications for long-term outcomes

are of utmost importance, it is a priority to define optimal intrauterine growth in

populations where nutrition and health needs are met (Bhutta, 2013; Villar et al., 2015).

Introduction

Bhutta Z, for the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). Introduction. BJOG 2013 Sep;120:1-2.

Villar J, Papageorghiou AT, Pang R, Monitoring human growth and development: a continuum from the womb to the classroom. Am J Obstet Gynecol 2015 Oct 1;213(4):494-9.

INTERGROWTH-21st

Module 2


and anthropometry

• The International Fetal and Newborn Growth Consortium for the 21st Century

(INTERGROWTH-21st) Project aimed to prospectively define fetal and newborn growth,

and postnatal growth among preterm infants (Bhutta, 2013).

• The INTERGROWTH-21st Project was a multicentre, multi-ethnic, population-based

project in eight urban study sites (Villar et al., 2015).

• Populations were first selected by geographical location (altitude, level of antenatal care,

absence or low levels of major known non-microbiological contamination) and then by

individual characteristics (e.g. maternal demographics and medical history) (Villar et al.,

2014).

Introduction

Bhutta Z, for the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). Introduction. BJOG 2013 Sep;120:1-2.

Villar J, Cheikh Ismail L, Victora CG, et al. International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). International standards for newborn weight, length,

and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet. 2014 Sep 6;384(9946):857-68.

http://dx.doi.org/10.1016/S0140-6736(14)60932-6

Villar J, Papageorghiou AT, Pang R, Monitoring human growth and development: a continuum from the womb to the classroom. Am J Obstet Gynecol 2015 Oct 1;213(4):494-9.

INTERGROWTH-21st

Module 2


and anthropometry

The INTERGROWTH-21st Project produced international standards for:

• Gestational age estimation

• First-trimester fetal size

• Fetal growth

• Newborn size for gestational age

• Postnatal growth of preterm infants

• Maternal gestational weight gain (also references for overweight women)

Introduction

https://intergrowth21.tghn.org/global-perinatal-package/crown-rump-length/

https://intergrowth21.tghn.org/global-perinatal-package/crown-rump-length/

https://intergrowth21.tghn.org/articles/intergrowth-21st-fetal-growth-standards/)

https://intergrowth21.tghn.org/articles/intergrowth-21st-newborn-size-birth-chart/

https://intergrowth21.tghn.org/articles/new-intergrowth-21st-international-postnatal-growth-standards-charts-available/

https://intergrowth21.tghn.org/site_media/media/medialibrary/2016/08/Maternal_weight_gain_package.pdf

INTERGROWTH-21st

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and anthropometry

• Implementing equipment calibration and measurement protocols at each

INTERGROWTH-21st Project’s study site ensured the highest quality anthropometric

data for the construction of the international standards (Cheikh Ismail et al., 2013).

• The Anthropometry Handbook used in this project describes how to perform accurate,

precise and standardised anthropometric measurements for the assessment of maternal

and newborn size.

Introduction

Cheikh Ismail L, Knight H, Bhutta Z, et al. Anthropometric protocols for the construction of new international fetal and newborn growth standards: the INTERGROWTH-21st Project. BJOG: An

International Journal of Obstetrics & Gynaecology. 2013 Sep;120:42-7

http://www.medscinet.net/Intergrowth/patientinfodocs/Anthropometry Handbook April 2012.pdf

INTERGROWTH-21st

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and anthropometry size

Maternal anthropometry

INTERGROWTH-21st

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Equipment

1. Adult Scale:

An example is the Seca 877 Scale used to measure maternal weight in the INTERGROWTH-21st project.

The scale has a capacity up to 200 kg, and precision to 100g below 150 kg and to 200g above 150 kg.

The scale has footmarks pasted on to show exactly where subjects stand.

The scale also has a built in spirit level to ensure that it is on a flat and level surface.

INTERGROWTH-21st. International Fetal and Newborn Growth Standards for the 21st Century: Anthropometry handbook. The International Fetal and Newborn Growth Consortium; 2012.

Seca 877 scale

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Equipment

2. Stadiometers:

For example, the 2 models of stadiometers used in the INTERGROWTH-21st Project were:

• Seca Stadiometer 242 (range 62-210 cm)

• Seca Stadiometer 264 (range 30-220 cm), which superseded the Seca Stadiometer 242 model, has a foot mat on which the person to be measured stands on and the display housing is integrated into the head stop.

These should measure adult height with an accuracy of ±2mm.


Seca Stadiometer 242 Seca Stadiometer 264

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Equipment

3. Body mass index (BMI) Calculator:

• The Seca BMI calculator 491 was used to calculate BMI of women in the INTERGROWTH-21st Project.

• BMI (in kg/m2) can also be calculated using the following formula of the body mass (in kg) divided by the square of the body height (in m), expressed as:

𝐵𝑀𝐼 =𝑊𝑒𝑖𝑔ℎ𝑡 (𝑘𝑔)

𝐻𝑒𝑖𝑔ℎ𝑡 2 (𝑚2)


Seca BMI calculator 491

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Equipment calibration

• Calibration of the adult scale and the stadiometer should be done twice a week at a minimum.

• It is not necessary to calibrate the BMI calculator.

• If the equipment is being transported for home visits or between clinics, it should be calibrated every day.


INTERGROWTH-21st

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Equipment maintenance

• Maintenance is important for keeping the equipment accurate and extending its

lifespan.

• All equipment should be handled with care during storage, transportation and use.

• It should be kept clean and stored and transported with care.

• Cool, dry and clean storage is a standard requirement for anthropometric

equipment. Different instruments and parts will require different materials for

cleaning and regular care.

To know more about the calibration and maintenance of the equipment, please

consult the Anthropometry Handbook.


https://intergrowth21.tghn.org/site_media/media/articles/Anthropometry_Handbook_April_2012.pdf

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Answer: To make sure that the equipment is working:

• It should be calibrated at least twice a week (more often if transported for home visits).

• It should be kept in a cool, dry, and clean storage.

• It should be transported carefully according to instructions.

Knowledge test

NO! NO! NO!

How do you make sure that the equipment for adult anthropometry is working?

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Measurement Technique: Height

1. Ask the subject to remove their shoes and any headwear or hair ornaments. Measure the thickness of any irremovable braids/corn rows with a small plastic ruler and deduct this from the total height at the end.

2. Turn the stadiometer on. “----” is displayed initially. Slightly move the head piece so that the present height appears on the display. Make sure the height is displayed in centimetres and not inches.

3. Raise the head piece far enough up so that the subject can stand under the headboard comfortably.


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Subject stands with back to the measuring rod, feet slightly apart, trunk balanced

over the waist, knees straight, arms and shoulders relaxed.

4. Ask the subject to stand with their back to the measuring rod, with feet slightly apart, the trunk balanced over the waist, knees straight, arms and shoulders relaxed as shown in the next slide.

5. The subject’s head, shoulders, buttocks, calves and heels should touched the measuring rod.

Ensure that the subject is not leaning against the rod.


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If the subject is much taller than the measurer, the latter should stand on a chair or stool to correctly position the subject.


INTERGROWTH-21st

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6. Ask the subject to look straight ahead. Their head should be held in the Frankfort horizontal plane.

7. Now slide the head stop down until it touches the top of the head. If using a stadiometer with a brake button like the Seca Stadiometer 462, remember to hold the brake button down when moving the head stop.

8. Ask the subject to take a deep breath; this straightens the spine and gives a consistent measurement.

9. Read off the measurement from the digital display and record the height as it appears on the display, i.e. to one decimal place.


Frankfort horizontal plane

The Frankfurt horizontal plane is the

plane running along the imaginary line

running between the corner of the eye

and the auditory canal.

Ensure to adjust the head position into

the Frankfurt horizontal plane.


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Answer: The standard and correct position to measure height is:

• The subject should stand with their back to the measuring rod, with feet slightly apart, the trunk balanced over the waist, knees straight, arms and shoulders relaxed.

• Their head should be in the Frankfurt horizontal plane.

• The subject’s head, shoulders, buttocks, calves and heels should touched the measuring rod but they should not lean on it.

Knowledge test

What standard position should the subject take to measure height?

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Measurement Technique: Weight

1. The woman should wear minimal, light clothing. If it is not possible/appropriate for her to remove heavy clothing, you should have available a list of weights for local, typical adult clothing items, the weights of which can be subtracted from the total weight before recording the value.

2. Ask the mother to empty her pockets, remove any heavy objects and take off her shoes.

3. Ensure the scale is on a perfectly flat surface with no obstructions. Remember that the Seca 877 scale has a built-in spirit level.

4. Turn the scale on by gently pressing a foot on the surface of the scale. The word SECA should appear, followed by 88:8888. When the value 0.0 appears, the scale is ready for use.


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5. Ask the mother to stand on the scale, placing her feet on the footmarks on the scale and remain still until the weight is stable on the display.

6. Read and record the weight as it appears on the display, i.e. to one decimal place.


Measurement Technique: Weight

INTERGROWTH-21st

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Answer:

Weight should be measured using a scale with an appropriate range and precision.

The subject should remove their shoes and ideally wear minimal, light clothing.

They should then stand on the scale until the weight stabilises.

Knowledge test

How do you measure weight?

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How to calculate BMI using the Seca BMI calculator

1. Activate the calculator by pressing ON/C

2. Press KG and enter the weight of the woman in kilograms.

3. Press M and enter the height of the woman in metres.

Please note that height is entered in metres not centimetres. To convert height in centimetres to metres, divide the value by 100. For example, if the height in centimetres is 160, the height in metres is 1.6.

4. Press the green BMI button.

5. Read and record the BMI value displayed on the screen


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How to calculate BMI using the Seca BMI calculator - Example

If the weight is 80.5kg, and height is 1.82 metres, then:

1. Press KG

2. Enter 80.5

3. Press M

4. Enter 1.82

5. Press BMI

6. The calculated BMI should be 24.3


INTERGROWTH-21st

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How to calculate BMI using a regular calculator - Example

Working the same example as previously, if the weight is 80.5kg, and height is 1.82 metres:

You need to divide the weight by the height, twice

1. Divide the weight by the height: 80.5 / 1.82 = 44.23 kg/m

2. Divide that number by the height again: 44.23 / 1.82 = 24.3 kg/m2


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How to interpret BMI?

We used the WHO BMI cut-off values to interpret the BMI.

Classification BMI principal

cut-off points

Underweight <18.50

Normal range 18.50 – 24.99

Overweight ≥ 25.00

Obese ≥ 30.00

Obese class I 30.00 – 34.99

Obese class II 35.00 – 39.99

Obese class III ≥ 40.00

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Answer:

1. BMI = 33.05 kg/m2

2. BMI = 21.71 kg/m2

Knowledge test

Exercise: using a calculator (e.g. a BMI calculator, one on your mobile phone or on a computer)

calculate the following BMI:

1. Height: 165cm, weight: 90kg

2. Height: 1.73m, weight: 65kg

INTERGROWTH-21st

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Height:

1. Remove shoes and hair ornaments

2. Subject stands with their back to measuring rod, feet slightly apart, trunk balanced over the waist, knees straight, arms and shoulders relaxed

3. Position head

4. Take deep breath in and stand tall

5. Headboard touches top of head

6. Record height as it appears on the display


Adult Anthropometry Checklist

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Weight:

1. Subject wears minimal, light clothing

2. Remove shoes and heavy objects

3. Zero scale

4. Subject stands centrally on scale

5. Read subject’s weight

6. If the weight of heavy clothing needs to be subtracted, please refer to your local list

Adult Anthropometry Checklist


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INTERGROWTH-21st standards for

Maternal gestational weight gain

INTERGROWTH-21st

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INTERGROWTH-21st standards for

Maternal Gestational Weight Gain

Cheikh Ismail L, Bishop DC, Pang R, et al: Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a

prospective longitudinal cohort study. BMJ 2016, 352(i):555.

• To describe patterns in maternal gestational weight gain (GWG) in healthy pregnancies with good maternal and perinatal outcomes.

• Healthy, well nourished, and educated women enrolled in the Fetal Growth Longitudinal Study component of the INTERGROWTH-21st Project, who had a body mass index (BMI) of 18.50-24.99 in the first trimester of pregnancy.

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Pre-requisite:

• Weight should be measured in the 1st trimester.

• Gestational age should be known either from LMP and/or dating scan (CRL at <14 weeks’ gestation).

• The standards represent cumulative gestational weight gain.

• It is not possible to infer more appropriate GWG pattern for women who are underweight (BMI < 18.50 kg/m2) or obese (BMI > 30.00 kg/m2) as our population consisted only of healthy women with a BMI range of 18.5- 29.99 kg/m2. Reference charts for overweight women are under preparation.

INTERGROWTH-21st

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and anthropometry

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How to use the GWG?

Example 1:

Dating scan visit at 9+3 weeks’ gestation, weight = 44.5kg

Visit at 25+0 weeks’ gestation, weight = 46.1 kg


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1. Calculate the weight gain between baseline and subsequent visit:


Baseline


Weight gain = 46.1 – 44.5 = 1.6 kg


Weight gain = 50.2 – 44.5 = 5.7 kg

2. Plot the weight on the charts:

- Find the correct gestational age (X-axis)

- Find the weight (Y-axis)

- Join the data on the plot

INTERGROWTH-21st

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and anthropometry

X

X

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How to use the GWG?

Example 2:




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1. Calculate the weight gain between baseline and subsequent visit:


Baseline


Weight gain = 64.3 – 54.4 = 9.9 kg


Weight gain = 71.0 – 54.4 = 16.6 kg

2. On the table find the gestational age in completed week (here 22 and 36)

3. Select the column with the weight gain the closest to your data

4. Read the top of the column for the centiles or z-scores

INTERGROWTH-21st

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and anthropometry

INTERGROWTH-21st

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How to read GWG?

• In the first example, the woman’s weight gain remained just below -2 z-scores throughout the pregnancy.

• In the second example, the women’s weight gain was above the 97th centiles at 22+2 weeks’ gestation but below the 90th centiles at 36+3 weeks’ gestation.

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How to interpret the GWG charts?

• There are no cut-off values for gestational weight gain.

• The standards (as part of first level nutritional screening) can be used to alert clinicians to deviations in weight, triggering clinical inquiries as to whether such deviations are associated with complications related to pregnancy, medical conditions, or eating disorders.

• Those standards should not be used, however, to tell women that deviations are due to pregnancy complications or recommending immediate behaviour changes as our data do not provide sufficient evidence for the standards to be interpreted in this way.

• Women who are underweight before pregnancy should be referred for nutritional advice and treatment if necessary. Also it is safe to suggest that during pregnancy such women should have GWG at least compatible with those of normal weight women.

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Knowledge test

Exercise:

Calculate the weight gain at the 2 time points and plot them on the graph.

Joan came for her dating scan at 13+1 weeks’ gestation. She was weighed by the

midwife, and her weight was 68.8kg.

She had an uneventful pregnancy until end of the 2nd trimester when she fainted. She

went to the hospital, she was then 31+6 weeks’ gestation and the midwife checked

her then and it was 80.8kg.

Finally she had a visit with her consultant at 37+0 to discuss delivery options and she

was weighted again at 86.7kg.

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and anthropometry

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Knowledge test

Answer:

Joan has an early weight (<14 weeks’ gestation) so the charts can be used.

At 31+6 weeks, her weight gain was 80.8 – 68.8 = 12 kg

At 37+0 weeks 86.7 – 68.8 = 17.9 kg

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and anthropometry

X

X

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• Reference for Maternal Gestational Weight Gain for overweight women are under preparation.

• Online resources to help health professionals implement these standards will be available in our Training Toolkit in the near future.

• Check for updates on https://intergrowth21.tghn.org/.

https://intergrowth21.tghn.org/

INTERGROWTH-21st

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and anthropometry

You have completed the module Assessing maternal weight gain and anthropometry and you should now be able to:

• List the instruments used for maternal anthropometry.

• Accurately measure maternal weight, height and Body mass index (BMI).

• Use the INTERGROWTH-21st Gestational Weight Gain Standard for normal-weight women.

INTERGROWTH-21st

Module 2


and anthropometry

References

• Bhutta Z, for the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). Introduction. BJOG: An International Journal of Obstetrics & Gynaecology. 2013 Sep;120:1-2. doi.org/10.1111/1471-0528.12032

• Cheikh Ismail L, Knight H, Bhutta Z, et al. Anthropometric protocols for the construction of new international fetal and newborn growth standards: the INTERGROWTH-21st Project. BJOG: An International Journal of Obstetrics & Gynaecology. 2013 Sep;120:42-7. doi.org/10.1111/1471-0528.12125

• Cheikh Ismail L, Bishop DC, Pang R, et al: Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study. BMJ 2016, 352(i):555. doi: 10.1136/bmj.i555.

• INTERGROWTH-21st. International Fetal and Newborn Growth Standards for the 21st Century: Anthropometry handbook. The International Fetal and Newborn Growth Consortium; 2012. Available from: https://intergrowth21.tghn.org/site_media/media/articles/Anthropometry_Handbook_April_2012.pdf

• Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, Lambert A, Papageorghiou AT, CarvalhoM, Jaffer YA, Gravett MG, Purwar M, Frederick IO, Noble AJ, Pang R, Barros FC, Chumlea C, Bhutta ZA, Kennedy SH, International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Lancet. 2014 Sep 6;384(9946):857-68. http://dx.doi.org/10.1016/S0140-6736(14)60932-6

• Villar J, Papageorghiou AT, Pang R, et al. Monitoring human growth and development: a continuum from the womb to the classroom. American Journal of Obstetrics & Gynecology. 2015 Oct 1;213(4):494-9. doi.org/10.1016/j.ajog.2015.07.002

http://dx.doi.org/10.1111/1471-0528.12032

http://dx.doi.org/10.1111/1471-0528.12125

https://intergrowth21.tghn.org/site_media/media/articles/Anthropometry_Handbook_April_2012.pdf

http://dx.doi.org/10.1016/S0140-6736(14)60932-6

http://dx.doi.org/10.1016/j.ajog.2015.07.002

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and anthropometry

Additional resources

• Ohadike CO, Cheikh-Ismail L, Ohuma EO, et al: Systematic Review of the Methodological Quality of Studies Aimed at Creating Gestational Weight Gain Charts. Adv Nutr 2016, 7(2):313-322. doi: 10.3945/an.115.010413

• Papageorghiou AT, Ohuma EO, Altman DG, Todros T, Cheikh Ismail L, Lambert A, Jaffer YA, Bertino E, GravettMG, Purwar M, Noble JA, Pang R, Victora CG, Barros FC, Carvalho M, Salomon LJ, Bhutta ZA, Kennedy SH, Villar J, International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet. 2014 Sep 6;384(9946):869-79. http://dx.doi.org/10.1016/S0140-6736(14)61490-2

• Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC, Lambert A, Carvalho M, Jaffer YA, Bertino E, Gravett MG, Altman DG, Purwar M, Noble JA, Pang R, Victora CG, Bhutta ZA, Villar J, International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol. 2014 Dec;44(6):641-8. http://dx.doi.org/10.1002/uog.13448

• Villar J, Altman DG, Purwar M, Noble JA, Knight HE, Ruyan P, Cheikh Ismail L, Barros FC, Lambert A, Papageorghiou AT, Carvalho M, Jaffer YA, Bertino E, Gravett MG, Bhutta ZA, Kennedy SH, International Fetaland Newborn Growth Consortium for the 21st Century. The objectives, design and implementation of the INTERGROWTH-21st Project. BJOG. 2013 Sep;120 Suppl 2:9-26, v. http://dx.doi.org/10.1111/1471-0528.12047

• Villar J, Giuliani F, Fenton TR, Ohuma EO, Ismail LC, Kennedy SH, INTERGROWTH-21st Consortium. INTERGROWTH-21st very preterm size at birth reference charts. Lancet. 2016 Feb 27;387(10021):844-5. http://dx.doi.org/10.1016/S0140-6736(16)00384-6

http://dx.doi.org/10.1016/S0140-6736(14)61490-2

http://dx.doi.org/10.1002/uog.13448

http://dx.doi.org/10.1111/1471-0528.12047

http://dx.doi.org/10.1016/S0140-6736(16)00384-6

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